When developing a gem, Gemfile.lock should not be checked into version control.

For the full rationale, see @wycats excellent article: http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/

.gitignore

@@ -3,3 +3,4 @@ pkg/*
 *.rbc
 *.swp
 .bundle
+Gemfile.lock

Gemfile.lock

@@ -1,31 +0,0 @@
-PATH
-  remote: .
-  specs:
-    guard-rails-assets (0.0.5)
-      guard
-      rake
-
-GEM
-  remote: http://rubygems.org/
-  specs:
-    diff-lcs (1.1.2)
-    guard (0.5.1)
-      thor (~> 0.14.6)
-    rake (0.9.2)
-    rspec (2.6.0)
-      rspec-core (~> 2.6.0)
-      rspec-expectations (~> 2.6.0)
-      rspec-mocks (~> 2.6.0)
-    rspec-core (2.6.4)
-    rspec-expectations (2.6.0)
-      diff-lcs (~> 1.1.2)
-    rspec-mocks (2.6.0)
-    thor (0.14.6)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  guard-rails-assets!
-  rake
-  rspec